In their logical analysis of theorems about disjoint rays in graphs, Barnes, Shore, and the author (hereafter BGS) introduced a weak choice scheme in second-order arithmetic, called the $\Sigma ^1_1$ axiom of finite choice (hereafter finite choice). This is a special case of the $\Sigma ^1_1$ axiom of choice ($\Sigma ^1_1\text {-}\mathsf {AC}_0$) introduced by Kreisel. BGS showed that $\Sigma ^1_1\text {-}\mathsf {AC}_0$ suffices for proving many of the aforementioned theorems in graph theory. While it is not known if these implications reverse, BGS also showed that those theorems imply finite choice (in some cases, with additional induction assumptions). This motivated us to study the proof-theoretic strength of finite choice. Using a variant of Steel forcing with tagged trees, we show that finite choice is not provable from the $\Delta ^1_1$-comprehension scheme (even over $\omega $-models). We also show that finite choice is a consequence of the arithmetic Bolzano–Weierstrass theorem (introduced by Friedman and studied by Conidis), assuming $\Sigma ^1_1$-induction. Our results were used by BGS to show that several theorems in graph theory cannot be proved using $\Delta ^1_1$-comprehension. Our results also strengthen results of Conidis.

Timely grazing decision-making requires routine information on the herbage mass (HM) and pasture growth rate (GR). The aim of this study was to compare the correspondence, cost and reliability of two indirect methods –the comparative yield method (COMPYLD) and the pasture-meter (CDAX)– to estimate HM and weekly GR of a 42 ha grazing area. Weekly assessments from April 2017 to October 2018 were made with both methods to estimate HM and GR of 13 individual paddocks. In addition, estimated GR were compared to aerial net primary productivity (ANPP) estimated using remote sensing (SAT). Estimated HM was 22% lower for COMPYLD than CDAX (HMCOMPYLD = 33 + 0.78*HMCDAX, R2 = 0.61, CV = 17%, RMSE = 291 kgDM/ha). The correspondence between methods of estimated weekly GR of individual paddocks was weak (GRCDAX = 0.18*GRCOMPYLD + 19.1, R2 = 0.05, CV = 73%, RMSE = 21.8 kgDM/ha/d). However, when integrated in three-week moving-averages, over the complete grazing area, COMPYLD and CDAX yielded similar GR up to 35 kg DM/ha/d. Accumulating GR of the grazing area over one year resulted similar to annual SAT-estimated ANPP. These results imply that, on one hand, decisions based on nominal HM, such as target HM and grazing strip size, would need to be adjusted depending on the method, but on the other hand, decisions based in temporal trends or GR, such as size and timing of set-aside areas for reserves, would be unaffected by method. Compared with COMPYLD, CDAX would be advantageous whenever high labour costs offset higher amortization, maintenance and fuel costs, provided there is an alternative in place to monitor during downtime periods.

The covid-19 pandemic has revived a longstanding, and understudied, trope in American politics: the association of immigrants with disease. There has been a great deal of scholarship on the economic, cultural, and criminal threat frames attached to immigrant groups in media coverage, but little to date has specifically examined how national and local sources have framed covid-19 in the context of immigrant communities. In this paper we analyze the prevalence of two different framings of the pandemic in national and local online news outlets over the first year of the pandemic: immigration as a public health threat to the nation, and covid-19 as a threat to immigrant communities within the nation. We find significant differences between national and local coverage, with the former more likely to frame immigration as a covid-19 threat, while local news outlets were more likely to discuss the threat the virus posed to already marginalized immigrant communities.

Napoliite, ideally Pb2OFCl, is a new fluoroxychloride mineral found in a specimen from a fumarole formed subsequent to the 1944 eruption of Vesuvius volcano, Naples Province, Italy. It occurs as well-shaped lamellar crystals up to 0.25 × 0.25 × 0.01 mm typically forming clusters up to 0.4 × 0.4 mm on the surface of volcanic scoria in association with anglesite, artroeite, atacamite, calcioaravaipaite, cerussite, challacolloite, cotunnite, hephaistosite, manuelarossiite, matlockite and susannite. Napoliite is colourless with white streak and adamantine lustre. It is brittle and has a laminated fracture. Cleavage is perfect on {001}. Dcalc = 7.797 g cm–3. The calculated mean refractive index is 2.10. Chemical composition (wt.%, electron microprobe) is: PbO 91.71, F 3.89, Cl 7.34, –O=(F+Cl) –3.30, total 99.64. The empirical formula calculated on the basis of 3 anions is Pb1.999O0.997F0.996Cl1.007. Raman spectroscopy confirms the absence of OH– groups and H2O molecules in the mineral. Napoliite is tetragonal, space group P42/mcm, a = 5.7418(11), c = 12.524(4) Å, V = 412.9(2) Å3 and Z = 4. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 3.860 (85) (111); 3.139 (20) (004); 2.914 (100) (113); 2.866 (63) (200); 2.118 (19) (204); 2.027 (19) (220); 1.665 (20) (313); and 1.642 (23) (117). The crystal structure was refined to R1 = 0.024 for 222 reflections with F > 4σ(F). It is based on lead oxide blocks derived from that of litharge PbO, which alternate with layers of chloride ions. Napoliite represents a new structure type with a unique order/disorder pattern of fluorine and oxygen atoms. The new mineral is dimorphous with rumseyite. It is named after the city of Naples (Napoli in Italian).

How does civilian protest shape civil war dynamics? Existing research shows that civilian protests against violence and war contribute to peace and restrain violence against civilians. There is less research on civilian protests that are at odds with peaceful conflict resolution, such as protests to salute armed actors, advocate against peace agreements, and oppose peacekeepers. This study develops a novel typology of wartime civilian protest that brings together protests to different ends, and theorizes the heterogeneous effects of protest on civil war dynamics. Using quantitative and qualitative evidence from new disaggregated and georeferenced event data from Côte d’Ivoire, the study demonstrates that—contingent on certain demands—protests were associated with violence against civilians, violence involving peacekeepers, and failed conflict resolution. These findings contribute new knowledge on how civilians shape the dynamics of civil war, and caution that nonviolent civilian action may not only be a force for de-escalation and peace.

This article appraises kin availability and migration timing on French-Canadian child mortality in an early twentieth-century North American industrial city. The analysis is based on the exploitation of an original dataset constructed by linking the 1910 census data (IPUMS-Full Count) for Manchester, New Hampshire to Quebec Catholic marriage records (BALSAC) and geocoding census data at the household level (Sanborn Fire Insurance Maps). Our results suggest that the presence of maternal and paternal grandmothers in the city living in different households were associated with reduced child mortality and that French-Canadian women who arrived in the United States as children or young adults experienced higher child mortality compared to second-generation French Canadians and those who migrated at a later age.

The control of a wing-in-ground craft (WIG) usually allows for many needs, like cruising, speed, survival and stealth. Various degrees of emphasis on these requirements result in different trajectories, but there has not been a way of integrating and quantifying them yet. Moreover, most previous studies on other vehicles’ multi-objective trajectory is planned globally, lacking for local planning. For the multi-objective trajectory planning of WIGs, this paper proposes a multi-objective function in a polynomial form, in which each item represents an independent requirement and is adjusted by a linear or exponential weight. It uses the magnitude of weights to demonstrate how much attention is paid relatively to the corresponding demand. Trajectories of a virtual WIG model above the wave trough terrain are planned using reward shaping based on the introduced multi-objective function and deep reinforcement learning (DRL). Two conditions are considered globally and locally: a single scheme of weights is assigned to the whole environment, and two different schemes of weights are assigned to the two parts of the environment. Effectiveness of the multi-object reward function is analysed from the local and global perspectives. The reward function provides WIGs with a universal framework for adjusting the magnitude of weights, to meet different degrees of requirements on cruising, speed, stealth and survival, and helps WIGs guide an expected trajectory in engineering.

A survey was conducted among Canadian tertiary neonatal intensive care units. Of the 27 sites who responded, 9 did not have any form of antimicrobial stewardship, and 11 used vancomycin for empirical coverage in late-onset-sepsis evaluations. We detected significant variations in the diagnostic criteria for urinary tract infection and ventilator-associated pneumonia.

The rapid and widespread establishment of domestic environmental courts and tribunals raises important questions regarding their implications for international environmental law and global environmental governance. I use an interdisciplinary, multi-method approach to consider the capacity of domestic environmental courts to identify and apply norms and principles of international environmental law in domestic opinions. I first review existing literature, identifying jurisdiction, judicial discretion, and a court's position in a legal system as key institutional determinants of this capacity. I then develop a typology of domestic environmental courts and tribunals, which suggests that, all else being equal, a court with national geographic jurisdiction that also enjoys attributes of broad subject-matter jurisdiction and discretion may be expected to be best equipped to implement norms and principles of international environmental law. Next, I integrate existing assessments of environmental court presence with original outreach and web research to identify all countries which possess environmental courts, and assess a subset of eight existing national-level institutions. The analysis of this subset highlights the diversity of institutional models that can incorporate theorized best practices. Based on these findings, I draw several theoretical conclusions: specifically (i) the relevance of environmental court research to individual- and institutional-level analysis in transnational and international environmental law, (ii) the need for further legal-institutional analysis in global environmental governance scholarship, and (iii) the opportunity for further interdisciplinary analysis of the role of domestic courts in environmental governance.

Over the past fifteen years, a narrative has developed that IR scholars have become a “cult of the irrelevant,” with declining influence on and engagement with policy debates. Despite these assertions, the evidence for limited policy engagement has been anecdotal. We investigate the extent of policy engagement—the ways in which IR scholars participate in policy-making processes and/or attempt to shape those processes—by surveying IR scholars directly about their engagement activities. We find policy engagement is pervasive among IR scholars. We draw on theories of credit-claiming to motivate expectations about how and when scholars are likely to engage with practitioners. Consistent with our expectations, much of this engagement comes in forms that involve small time commitments and provide opportunities for credit-claiming, such as media appearances and short-form, bylined op-eds and blog posts. However, sizable minorities report engaging in consulting activities not for attribution/publication and writing policy briefs, and a majority of respondents indicate they engaged in these activities several times a year or more. We find only small differences in engagement across gender and rank. Our results demonstrate that, for IR scholars, some form of policy engagement is the norm.

The stability of divided societies is an important and recurring concern in political science research. It has been suggested that distinctive socialization processes in the different regions of divided societies will lead to diverging trends in public opinion. Therefore, we investigate trends in public opinion on key political issues and attitudes in three divided societies: Canada (Quebec), the United Kingdom (Scotland) and Spain (Catalonia). Using over two decades of survey data, we show that these distinct communities indeed have a particular ideological profile but also that there is no indication these differences become larger over time. In other words, we do not observe any evidence for an increasing lack of public opinion coherence in these divided societies. We conclude with some observations on why divergence could not be observed at the level of public opinion but might still be present at the level of party elites.

A low second-to-fourth digit ratio (2D:4D) is a purported biomarker of increased intrauterine androgenic exposure, presumably linked to postnatal behavior. We aimed to examine the associations between 2D:4D and adolescence behavior problems expected from high (externalizing and attention problems) or low (internalizing problems) prenatal androgen exposure. We conducted a cross-sectional study of 1042 Colombian schoolchildren aged 11–18 y. We examined whether caliper-assessed 2D:4D was associated with behavior problems per the Youth Self-Report questionnaire. Mean problem standardized score point differences were estimated between hand- and sex-specific quintiles of 2D:4D with use of multivariable linear regression. Lower right-hand 2D:4D was associated with decreased externalizing and internalizing behavior problem scores. Corresponding lowest-to-median quintile adjusted mean differences (95% CI) were −4.6 (−7.5, −1.7) and −3.5 (−6.4, −0.6) points in boys; and −3.4 (−5.9, −0.9) and −3.5 (−6.2, −0.8) points in girls. Lower right-hand 2D:4D was also related to less attention and thought problems in boys, and to less social problems among girls. Associations were nonlinear, apparent only below 2D:4D medians, and stronger with the right than the left hand. In conclusion, right-hand 2D:4D is related to behavior problems in adolescence in directions that are not fully consistent with an androgenic exposure origin.

Previous research has demonstrated that family transitions, specifically births and deaths of preceding and following generations within families, are associated with individuals’ later-life wellbeing and health. However, lifecourse, family systems and role theories suggest that this relationship might be complex because, as individuals age, they can experience multiple such events and their effects might be interconnected. Therefore, this study asks whether and how transitions into and out of multiple intergenerational family roles are associated with later-life wellbeing and health. We account for the occurrence, timing and ordering of the parents’ death and the birth of the first child and grandchild. To this end, we use the concept of ‘generational placement trajectories’. They capture the vertical position of individuals in their intergenerational family over age and reflect the changing family roles and kinship reservoir of individuals across their lifecourse. Applying sequence, cluster and regression analyses to data from the German Ageing Survey (N = 3,617), we investigate associations between generational placement trajectories from birth to age 60 and four dimensions of later-life wellbeing and health, namely life satisfaction, depressiveness, functional limitations and physical health problems. Results support, first, the notion of salutary effects of a larger kinship reservoir and multiple social roles in the family and, second, indicate that ‘off-time’ transitions are associated negatively with various later-life wellbeing and health outcomes. Importantly, the effect of temporal deviations from the ‘normative’ family lifecourse might be affected by individual socio-economic differences. We enhance previous research by demonstrating that the occurrence, timing and ordering of transitions into and out of multiple kin relations and family roles across the lifecourse relate to individuals’ later-life wellbeing and health.